It is a common practice to provide human medical patients with artificial ventilation means during surgery or in emergency situations. For example, frequently accident victims require CPR or intubation by the paramedic in an emergency vehicle or by an anesthesiologist in an operating room. Intubation is accomplished by insertion of an endotracheal tube into the patient's airway passage. The endotracheal tube may be either a single lumen endotracheal tube or a double lumen endotracheal tube. The single lumen endotracheal tube is an elongated tube that extends into the trachea of a patient upon intubation and includes one inflatable cuff on its distal end. The double lumen endotracheal tube is commonly referred to as an endobronchial tube and not only has one lumen which extends into the trachea, but a further longer lumen which extends into the bronchus upon intubation. The double lumen endotracheal tube or endobronchial tube includes two inflatable cuffs on its distal ends, as will be further discussed. The present invention relates to both the single lumen endotracheal tube and the double lumen endotracheal tube.
The single lumen endotracheal tube is inserted into the patient by placing it first into the patient's oral cavity and then manually manipulating the tube through the vocal cords and into the tracheal cavity. As stated above, similar manipulation is used to insert a double lumen endotracheal (endobronchial) tube into the patient, wherein the first lumen extends into the trachea, and the second lumen into the bronchus. A laryngoscope is utilized during the insertion of each endotracheal tube to lift the patient's tongue and to provide direct visualization of the vocal cords.
The single lumen and the double lumen endotracheal tubes each include an inflatable, balloon-like upper tracheal cuff near its distal end. The double lumen endotracheal tube further includes a smaller lower bronchial cuff on the distal end of the longer bronchial lumen. The cuffs are thin walled, high volume and low pressure, and are designed so as not to compromise the blood flow in the tracheal or bronchial wall when inflated. The cuffs are inflated by detachable syringes that are connected to channels at the proximal end of the endotracheal tube and function to form seals between the tube and the inner walls of the trachea, and further in the bronchus in the double lumen endotracheal tube. The seals formed by the inflated cuffs preclude the air that has been forced into the patient's lungs from escaping through the trachea or bronchus. Additionally, the seals formed by the inflated cuffs provide a barrier to blood and secretions. The cuffs are extremely thin to facilitate passage of the tube through the oral cavity and subsequent inflation and accordingly, are susceptible to tearing.
The insertion of existing prior art single and double lumen endotracheal tubes is often a problem due to difficult airways in the patient caused by unusual anatomy or other abnormalities of the teeth or oral cavity. Insertion of the tubes into the patient's oral cavity is further complicated by the bulky and cumbersome shape of the tube which serves to further exacerbate existing difficulties. Because of the awkward design of the tube in conjunction with the fragility of the cuffs, the cuffs frequently tear on the patient's teeth or are punctured by the laryngoscope blade during the intubation process. The tracheal cuff is especially susceptible to tears due to its larger diameter and its increased exposure to the patient's oral cavity. Moreover, the laryngoscope is positioned and maintained in the oral cavity after the smaller bronchial cuff of the double lumen endotracheal tube has passed through the oral cavity and is being manipulated past the vocal cords and into the bronchus. Accordingly, it is the larger tracheal cuff of both the single and double lumen endotracheal tube which is primarily exposed to the laryngoscope and to the patient's teeth.
When a tear occurs in the cuff, the tube must be removed from the patient and discarded, and the intubation process must be re-initiated and repeated until proper insertion of the tube is achieved. Not only is it expensive to replace the tubes due to a cuff tear, but the time involved in removal of the tube for replacement thereof may be critical to the survival of the patient.
Conventional attempts to prevent the cuff from tearing, such as repositioning the jaw, lubricating the cuff, and padding the teeth have proven to be ineffective.